The purpose of this K24 MidCareer Investigator Award is to support Dr. Marina Tolou-Shams, a child clinical psychologist who has been continuously funded since 2007, to conduct research and to mentor others in the areas of substance use, mental health, and co-occurring health risk behaviors for justice-involved youth. This candidate proposes to utilize K24 support to a) expand her existing program of juvenile justice behavioral health research into the field of digital behavioral health intervention and b) mentor junior PhD and MD researchers in rapidly moving the science forward in identification and dissemination of ways to improving substance use, mental and sexual health outcomes for youth in the juvenile justice system, including the development and testing of digital health approaches for improved outcomes. Taking advantage of a rich institutional environment, the candidate has assembled a group of expert interdisciplinary collaborators to ensure that she and her mentees will be on the cutting edge of digital behavioral health research with vulnerable populations. Digital mobile health (mHealth) technologies have been increasingly demonstrated as an efficacious, low-cost way of reaching underserved, vulnerable, populations to engage them into and/or deliver quality care. Mobile health therefore represents a promising approach to improving substance use and psychiatric outcomes for justice-involved youth. Dr. Tolou-Shams? research project will focus on conducting a pilot trial of a tailored SMS text-messaging platform to engage court-involved, non-incarcerated (CINI) youth into substance use or dual diagnosis treatment services. Study aims include 1) determining whether and how a tailored dyadic (youth/caregiver) SMS text-messaging intervention increases CINI youth treatment engagement and 2) identifying real-world factors critical to consider for justice and behavioral health systems eventual adoption and sustainability of an SMS text- messaging intervention for youth treatment engagement. This K24 research and protected time for mentoring will lead to ways in which the field will learn about how to develop, test and implement individual and system-level digital health interventions for unmet juvenile justice substance use and mental health treatment services needs across various points in the continuum of care (e.g., screening, referral, treatment engagement, treatment delivery).